|ALI, SHAHIN - University College Dublin|
|GUNUPURU, LOKANADHA - University College Dublin|
|KUMAR, G.B. - University College Dublin|
|KHAN, MOJIBUR - University College Dublin|
|Scofield, Steven - Steve|
|NICHOLSON, PAUL - John Innes Center|
|DOOHAN, FIONA - University College Dublin|
Submitted to: BMC Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2014
Publication Date: 8/12/2014
Citation: Ali, S.S., Gunupuru, L.R., Kumar, G.S., Khan, M., Scofield, S.R., Nicholson, P., Doohan, F.M. 2014. Plant disease resistance is augmented in uzu barley lines modified in the brassinosteroid receptor BRI1. Biomed Central (BMC) Plant Biology. 14:227.
Interpretive Summary: The semi-dwarf variety of barley known as "Uzu" is unusual in having significantly greater resistance to a number of fungal diseases, including: leaf blast, take-all, eyespot, as well as crown and stem rot. Previous work established that the semi-dwarf trait of uzu results from a mutation of the BRI1 gene that encodes a receptor for the plant hormone, brassinosteroid. This paper shows that the increased broad-spectrum disease resistance in the uzu barley lines also is a result of the mutation in the BRI1 gene. This information will be valuable in future efforts to develop crops with improved disease resistance.
Technical Abstract: Brassinosteroid hormones regulate many aspects of plant growth and development and the membrane receptors BRI1 and BAK1 are central players in the upstream signaling cascade. Semi-dwarf ‘uzu’ barley carries a mutation in a conserved domain of the kinase tail of BRI1 and this mutant allele is recognized for its positive contribution to both yield and lodging resistance. Here we show that uzu barley exhibits enhanced resistance to a range of pathogens. Enhanced resistance in uzu was due to a combination of preformed, inducible and de-repressed defense responses, as determined by a combination of transcriptomic and biochemical studies. A combination of gene silencing and gene expression studies were used to determine that while the uzu mutation attenuates downstream brassinosteroid signaling, disease resistance requires the presence of the mutated form of BRI1. Thus we conclude that the introgression of uzu variants into barley and other crops will help reduce disease-associated yield losses.